Improvement in sewing-machines



O. N. STODDARD.

Sewing Machine.

Patented Aug. 23, 1859.

Witnesses:

UNTTED STATES PATENT FEIc IMPROVEMENT IN SEWIN G-MACHINES.

, Specification forming part of Letters Patent No. 25,223, dated August 23, 1859.

To all whom it may concern Beit known that 1, ORANGE N. STODDARD, of Miami University, Oxford, Butler county, Ohio, have invented a certain new and useful Improvement in Sewing-Machines and I hereby declare the following to be a full and exact description of the same, reference being had to the accompanying drawings, making part of this specification.

The improvement relates to that class of double-thread sewing-machines in which the lock is effected by the rotation of a peculiar bobbin-holder called the hook, in passing around which the loop is temporarily detained by a device familiarly known as the loopcheck or pad, the object of which is to prevent the casualty ofa broken thread, in consequence of a second engagement of the hook with the same loop.

The subject of the present invention is a yielding metallic loop-check which enters a channel or groove in a portion of the periphery of the. hook, its advantages being superior efficiency and durability, and non-liability to derangement.

M .QI n the annexed drawings, Figure l is a perspective view, exhibiting the combination of the hook and loop-check. Fig. 2 is an axial section at 40 as, Fig. 1.

The hook A may be formed like those now in use, with the exception of a shallow rounded groove or channel, a, which, commencing in the periphery of the hook, near its point, is continued in the plane of rotation for near or about half the circuit of the hook, dying out at each end in the beveled or chamfered por- .tions of the latter. A transverse section or the groove a is seen in Fig. 2.

The loop-check consists of a slender steel bar or rod, B, pivoted at one end to the frame of the machine, and at the other end formed with a rounded point, which enters the groove to as far as possible without actual contact.

.0 is a slotted post which holds the bar B in a correct position, but allows it alimited play in the plane of rotation of the hook to accommodate it to the shortening of the thread.

b is a spring which maintains the necessary pressure upon the bar B, and returns it to its lowest position when released by the thread. The bar B must be applied at that part of the hook at which the thread can be most advantageously detained, and should, when at to the grooved periphery of the hook may also be regulated by a set-screw.

Instead of the form described, the end of the bar B may be notched or nicked to receive a corresponding fin or feather around the first half of the periphery of the hook, and the bar B may be placed at an angle more or less oblique to the plane of the groove a; but it is proper to state that I prefer the form selected for the illustration, as that which actual test by use has proved to be efficient.

.The bar B, instead of being hinged, may be fixed transversely to a shank which may slide in staples and be retracted by a spiral or gum spring; or the said bar may be arranged to vibrate upon an axis coincident with that of the hook, its point being turned around so as to approach the hook and operate in connection therewith without contact iii either manner described above.

From a careful observation of the operation of this class of sewing-machines it will be per ceived that a considerable shortening of the thread occurs between the period of first detention and that of its release. An unyielding loop-check, by resisting this shortening, seriously endangers breaking the thread, and as the shortening occurs from but one side of the hook it is disadvantageous for the detention of the thread to be accompanied by any compressing of the same between the loop-check and hook. It will also be seen that the short ening of the loop varies with different thick nesses of fabric and different lengths of stitch. Another serious objection to the customary leather pad is the severe wear to which it is subjected, rendering adjustment occasionally necessary, especially when changing from the use of coarse to fin'er thread.

The following are among the advantages which are believed to be peculiar to this construction and arrangement of loopcheck:

First, it is subject to no perceptibleamount of wear, needs no readjustment, and may be as permanent and enduring as the hook itself; second, itis adapted to yield to the shortening of the thread, incident to the motion of the machine, and also to compensate for variations in the length of the stitch or the thickness of the cloth, thus avoiding the danger both of breaking the thread by too severe tension, and missing stitches by the thread being drawn too taut to form aloop at the right instant; third, the finest thread is effectually detained without being compressed between the-loop-check and hook, so that, although only hard .sub-

stances are used, the wearing effect upon the thread is much less severe than with the customary leather pad.

I claim as new and of my invention herein, and desire to secure by Letters Patent- The yielding metallic loop-check B b, operating in combination with a grooved hook, A a, or its described equivalent, in the manner and for the purpose set forth.

In testimony of which invention I hereunto set my hand.

I O. N. STODDARD. \Vitnesses:

Gno. H. KNIGHT, C. STEEMER. 

